1. Field of the Invention
The present invention relates to a burner having two hollow, conical section bodies arranged for define a conical space.
2. Discussion of Background
U.S. Pat. No. 4,932,861 to Keller et al. discloses a premixing burner of double-cone type of construction which essentially comprises two hollow, conical sectional bodies which are nested one inside the other and aligned in the direction of flow and whose respective longitudinal symmetry axes are mutually offset. This mutual offset forms longitudinal ducts or air-inlet slots, between adjacent walls of the sectional bodies, through which ducts or air-inlet slots a combustion-air flow passes tangentially into the conical hollow space. At least one fuel nozzle is positioned in this conical hollow space. This burner represents a leap in quality compared with the prior art as regards flame stabilization, efficiency and pollutant emissions. However, if the load range of such a burner, for example during modulated operation, has to be changed, under certain boundary conditions the flame front, stable per se, can shift upstream and become stable at a poor location for the burner itself as well as for the formation of emissions. This results in problems including overheating of the burner, deterioration in the pollutant emissions and the occurrence of pulsations. In the face of such a situation it is inevitable that the possible load range is restricted.